.TH std::filesystem::path::compare 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::filesystem::path::compare \- std::filesystem::path::compare

.SH Synopsis
   int compare( const path& p ) const noexcept;                 \fB(1)\fP \fI(since C++17)\fP
   int compare( const string_type& str ) const;                 \fB(2)\fP \fI(since C++17)\fP
   int compare( std::basic_string_view<value_type> str ) const;
   int compare( const value_type* s ) const;                    \fB(3)\fP \fI(since C++17)\fP

   Compares the lexical representations of the path and another path.

   1) If root_name().native().compare(p.root_name().native()) is nonzero, returns that
   value.
   Otherwise, if has_root_directory() != p.has_root_directory(), returns a value less
   than zero if has_root_directory() is false and a value greater than zero otherwise.
   Otherwise returns a value less than, equal to or greater than 0 if the relative
   portion of the path (relative_path()) is respectively lexicographically less than,
   equal to or greater than the relative portion of p (p.relative_path()). Comparison
   is performed element-wise, as if by iterating both paths from begin() to end() and
   comparing the result of native() for each element.
   2) Equivalent to compare(path(str)).
   3) Equivalent to compare(path(s)).

.SH Parameters

   p   - a path to compare to
   str - a string or string view representing path to compare to
   s   - a null-terminated string representing path to compare to

.SH Return value

   A value less than 0 if the path is lexicographically less than the given path.

   A value equal to 0 if the path is lexicographically equal to the given path.

   A value greater than 0 if the path is lexicographically greater than the given path.

.SH Exceptions

   2,3) May throw implementation-defined exceptions.

.SH Notes

   For two-way comparisons, binary operators may be more suitable.

.SH Example


// Run this code

 #include <filesystem>
 #include <iostream>
 #include <string_view>
 namespace fs = std::filesystem;

 void demo(fs::path p1, fs::path p2, std::string_view msg)
 {
     std::cout << p1;
     const int rc = p1.compare(p2);
     if (rc < 0)
         std::cout << " < ";
     else if (rc > 0)
         std::cout << " > ";
     else
         std::cout << " == ";
     std::cout << p2 << " \\t: " << msg << '\\n';
 }

 int main()
 {
     demo("/a/b/", "/a/b/", "simple");
     demo("/a/b/", "/a/b/c", "simple");
     demo("/a/b/../b", "/a/b", "no canonical conversion");
     demo("/a/b", "/a/b/.", "no canonical conversion");
     demo("/a/b/", "a/c", "absolute paths order after relative ones");
 }

.SH Output:

 "/a/b/" == "/a/b/"      : simple
 "/a/b/" < "/a/b/c"   : simple
 "/a/b/../b" > "/a/b" : no canonical conversion
 "/a/b" < "/a/b/."    : no canonical conversion
 "/a/b/" > "a/c"              : absolute paths order after relative ones

   Defect reports

   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.

      DR    Applied to   Behavior as published              Correct behavior
   LWG 2936 C++17      compared all path elements root name and root directory handled
                       directly                   separately

.SH See also

   operator==
   operator!=
   operator<
   operator<=
   operator>
   operator>=
   operator<=>          lexicographically compares two paths
   \fI(C++17)\fP              \fI(function)\fP
   \fI(C++17)\fP\fI(until C++20)\fP
   \fI(C++17)\fP\fI(until C++20)\fP
   \fI(C++17)\fP\fI(until C++20)\fP
   \fI(C++17)\fP\fI(until C++20)\fP
   \fI(C++17)\fP\fI(until C++20)\fP
   (C++20)
